Project Summary The overall goal of the pre-doctoral training program in Quantitative Integrative Biology (QIB) at University of California, San Diego (UCSD) is to bring together faculty with broad and complementary research expertise to train graduate students to investigate current questions in systems physiology. The collective behavior exhibited by groups of cells in developing, regenerating and homeostatic tissues and organs is substantially more than the sum of its parts, and requires continuous multi-level collaborations between cells, tissues, and organs. To understand the nature and mechanisms underlying such collaborations, the QIB program includes a diverse collection of training faculty who use a variety of quantitative tools and approaches to address questions related to organismal development and regeneration, tissue and organ physiology, and the basis of these phenomena in cell-cell communication, interactions and collective cell behaviors. Recognizing that cells and tissues of an organism do not live in isolation, but in a symbiotic state with complex microbial communities affecting the health of the host, QIB also includes a group of faculty with expertise in the human microbiome, who are developing approaches to predict and modulate microbiome composition, and engineer its behavior to affect disease progression. Altogether, the QIB program comprise of 27 quantitatively-oriented faculty from the UCSD Division of Biology, Division of Physical Sciences, and from the Medical School and Pharmacy School, all located in close proximity to each other on the UCSD campus. This group of faculty boasts of spectacular research accomplishments, bringing almost $29M annually in total research funding. The central element of the QIB program is to train students to develop experimental tools and integrate modern theoretical methods into their research in quantitative physiology. This program is a component of a broader campus wide Quantitative Biology (qBio) initiative, which has received substantial institutional support, including 2,000 sq. ft. of dedicated space and $1M investment in unique equipment for a modern teaching lab dubbed the qBio ?hacker lab?, aimed to train students not only to work with modern tools and methodology for life science studies, but to endow them with the ability and mind-set to modify existing tools and adapt them to specific research projects. This proposal aims to train 6 pre-doctoral students each year, with 2 additional matching slots with funds from the Office of Graduate Studies and the Executive Vice Chancellor, starting in their second year of graduate studies for a 12-month period. The proposal establishes a special curriculum for students from one of four departments/programs: Department of Physics, Department of Chemistry & Biochemistry (both in the Division of Physical Sciences), Division of Biological Sciences, and the Graduate Program in Biomedical Sciences. The curriculum includes multiple courses in quantitative methods in physiology, year-long training in experimental tool development and application (the qBio hacker lab), and mentoring in professional growth (critical reading, research presentation, personal and career guidance). The pool of students qualified for this new training program is excellent ? 52 out of the 71 (73%) of the current graduate students in our faculty's labs [or 132 out of 178 (74%) within the past 10 years] would have been eligible to participate in the program. Given the strength of UCSD in interdisciplinary and collaborative research, the outstanding pool of qualified trainees, and a broad and complementary set of training faculty with superb research, training, and funding record, we believe that our QIB program offers an excellent and unique training opportunity for quantitative-oriented research in the very important field of systems physiology.